/**
 * @description 全屏/退出全屏模式函数
 * @param fullScreen 浏览器全屏模式
 * @param exitFullScreen 退出浏览器全屏模式
 */
// 全屏模式
function fullScreen() {
  let el = document.documentElement;
  let rfs = el.requestFullScreen || el.webkitRequestFullScreen || 
      el.mozRequestFullScreen || el.msRequestFullScreen;
  if(typeof rfs != "undefined" && rfs) {
    rfs.call(el);
  } else if(typeof window.ActiveXObject != "undefined") {
    //for IE，这里其实就是模拟了按下键盘的F11，使浏览器全屏
    let wscript = new ActiveXObject("WScript.Shell");
    if(wscript != null) {
        wscript.SendKeys("{F11}");
    }
  }
}
// 退出全屏
function exitFullScreen() {
  let el = document;
  let cfs = el.cancelFullScreen || el.webkitCancelFullScreen || 
      el.mozCancelFullScreen || el.exitFullScreen;
  if(typeof cfs != "undefined" && cfs) {
    cfs.call(el);
  } else if(typeof window.ActiveXObject != "undefined") {
    //for IE，这里和fullScreen相同，模拟按下F11键退出全屏
    let wscript = new ActiveXObject("WScript.Shell");
    if(wscript != null) {
        wscript.SendKeys("{F11}");
    }
  }
}